lkml.org 
[lkml]   [2001]   [Aug]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    On August 19, 2001 11:11 pm, Otto Wyss wrote:
    > I recently wrote some small files to the floppy disk and noticed almost nothing
    > happened immediately but after a certain time the floppy actually started
    > writing. So this action took more than 30 seconds instead just a few. This
    > remembered me of the elevator problem in the kernel. To transfer this example
    > into real live: A person who wants to take the elevator has to wait 8 hours
    > before the elevator even starts. While probably everyone agrees this is
    > ridiculous in real live astonishingly nobody complains about it in case of a disk.

    My early flush patch, posted a month or so ago, takes care of this nicely.
    I'm just waiting for 2.5 to roll around to do some more work on it.

    > [...]
    > Could anybody produce any real figures to prove/disprove my theory? Could
    > anybody benchmark the disk access for the 3 waiting times (0, 200ms 30sec) with
    > different loads?

    Your theory is correct. I implemented the idea, took measurements, and found
    dramatic performance improvements under some loads, while getting worse on
    none. You can search lwn.net for a nice writeup by Jonathan Corbett.

    --
    Daniel
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 12:58    [W:4.524 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site